1. Field of the Invention
The present invention relates to an internal combustion engine control system that controls an internal combustion engine, and particularly to an internal combustion engine control system that controls an internal combustion engine by utilizing a crank angle sensor so as to localize the position of a piston of the internal combustion engine.
2. Description of the Related Art
To date, for example, with regard to an idling stop vehicle, there has been provided a system in which, when an engine is restarted after the internal combustion engine (referred to as an engine, hereinafter) is stopped through an idling stop method, the position of a piston is determined by use of a piston position determination method the same as that utilized at a time when the engine is normally started, and based on the determined piston stopping position, fuel injection control is performed sequentially from the initial stage of the restarting of the engine.
However, in the case of such a conventional system, when an engine is restarted after the engine is stopped through the idling stop method, there is utilized the piston position determination method the same as that utilized at a time when the engine is normally started; thus, there has been a problem that it takes a lot of time to restart the engine after the engine is stopped through the idling stop method.
Accordingly, there has been proposed a system (e.g., refer to Japanese Patent Application Laid-Open No. H7-83093) in which there is stored the position of a piston at a time when the engine is stopped through the idling stop method, and when the engine is restarted, the stored piston position is utilized so that there is reduced the time for determining the piston position.
Moreover, there has been proposed a system (e.g., refer to Japanese Patent No. 3896640) in which, by controlling an apparatus such as an engine load or an auxiliary apparatus when an engine is stopped, a piston of the engine is stopped at the target position.
Furthermore, to date, there has been proposed a system (e.g., refer to Japanese Patent No. 4244651) in which, in the process of stopping an engine, the engine stopping position, i.e., the piston stopping position is estimated based on a parameter for representing the movement of the engine and a parameter for preventing the movement of the engine.
Still moreover, to date, there has been proposed a system (e.g., refer to Japanese Patent Application Laid-Open No. 2005-233622 and Japanese Patent Application Laid-Open No. 2005-256842) in which, in order to accurately determine the piston position at a time when the engine is stopped, there is utilized a sensor that enables a crank angle to be accurately detected even when the crank shaft reverses at a time when the engine is stopped.
However, in the case of the conventional system disclosed in Japanese Patent Application Laid-Open No. H7-83093, measures for a rebound (reversal) at a time an engine is stopped is insufficient; thus, the engine stopping position may not accurately be stored.
Moreover, in the case of the conventional system disclosed in Japanese Patent No. 3896640, it is required to control an apparatus such as a load or an auxiliary apparatus for making an engine stop at the target position; therefore, control becomes complicated, and when the apparatus such as a load or an auxiliary apparatus is changed, it is required to change the contents of the control.
Still moreover, in the case of the conventional system disclosed in Japanese Patent No. 4244651, it is complicated to perform calculation by utilizing a parameter for representing the movement of an engine and a parameter for preventing the movement of the engine, and at the same time, the parameter inherent to the engine needs to be obtained through a physical model or experimental data; thus, there is also required an expensive calculation device for utilizing the physical model.
Furthermore, in the case of the conventional system disclosed in Japanese Patent Application Laid-Open No. 2005-233622 and Japanese Patent Application Laid-Open No. 2005-256842, a crank angle sensor having a reversal detection function is utilized; therefore, the cost is raised compared with the case where an ordinary crank angle sensor is utilized. Even in the case where an encoder that directly outputs an accurate angle is utilized as a crank angle sensor, the encoder itself is expensive; at the same time, there is also required an expensive calculation device for decoding the output signal of the encoder.